Combination bumper sub and safety joint unit



p 1, 1953 K. R. STOHN 2,650,797

COMBINATION BUMPER SUB AND SAFETY JOINT UNIT Filed March 20, 1950 2 SheetsSheet l m I w III N I I (S 2 (3 'u.

g; I I I II I l I I w Q N I A *3 INVENTOR.

K'en'dcll R. Srohn BY I Wvfl M J ATTORNEY-S Sept. 1, 1953 K. R. STOHN COMBINATION BUMPER SUB AND SAFETY JOINT UNIT Filed March 20, 1950 2 Sheets-Sheet 2 "NEE E .m v

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INVENTOR. Kend u I R. Stohn BY 7 V .ATTO R N EYS Patented Sept. 1, 1953 UNITED STATES PATENT OFFICE COMBINATION BUMPER SUB AND SAFETY JOINT UNIT 7 Claims.

This invention relates to apparatus for drilling bores in earth formations and more particularly to a tool for embodying in a drilling string which will permit a bumping or jarring action to be imparted to the string to loosen any stuck portion thereof or to permit one portion of the string to be completely disconnected from another portion as desired.

One of the objects of my invention is to produce an improved unitary structure for a rotary drilling string in which is embodied means to accomplish a jarring action and also a disconnection of portions of the string.

A further and more specific object is to produce an improved combination bumper sub and safety joint unit for use in drill strings of rotary drilling rigs.

Yet a further object is to provide in such a combination structure bumping or jarring means which will permit both an upward or downward bumping or jarring action on the drill string whenever the structure is conditioned for any jarring or bumping action.

Another object is to provide a combination bumper sub and safety joint which normally will produce a rigid connection in the drilling string, but can easily and quickly be conditioned by different degrees of reverse rotations of the drill pipe to provide a bumping or jarring structure or complete disconnection of the string.

Yet another object is to produce an improved combination bumper sub and safety joint which is simple in construction, economical to manufacture, very eflicient in operation, and easily and quickly conditioned for either bumping or disconnection.

Other objects will become apparent from the following description taken in connection with the accompanying drawing in which:

Figures 1 and 2 are views showing the entire unit embodying my invention, Figure 1 being a view of the upper portion thereof and Figure 2 being a view of the lower portion thereof, said views having parts broken away and in section and showing the structure in its inoperative or rigid condition employed during drilling;

@Figures 3 and 4 are two views similar to Figures land 2, respectively, but showing the structure conditioned for bumping or jarring action;

Figure 5 is a cross sectional view taken on the line 5-5 of Figure 2; and

Figure 6 is a perspective cross sectional view showing, in a different manner, the relation between the same parts which are shown by Figure5."

Referring to the drawings in detail and first to Figures 1, 2, 5 and 6, my improved combination bumper sub and safety joint unit is connectable in the drilling string at any point desired above the drill collars. In Figures 1 and 2 the numeral I0 indicates the lower end of a drill pipe portion which extend to the top of a well bore and numeral H indicates the upper end of a drill pipe portion which extends on down into a well bore and to which,'at its lower end, is connected the drill collars and drill bit or other tool. The top of the drill collars may replace the drill pipe portion ll if the unit is desired to be just above the drill collars.

The unit has a mandrel M of considerable length and this mandrel has a bore l2 so that drilling fluid can be circulated through the unit from the upper portion of the drill pipe to the lower portion. The upper end portion I3 of the mandrel is of the same diameter as the drill pipe and is provided with internal V threads [4 so that it can be directly connected to the male threads [5 on the lower ends of the drill pipe section II]. The threads l4 and [5 provide the same joint structure as is commonly used between sections of drill pipe. The main section it of the mandrel is of a diameter considerably smaller than the upper end l3 and between these portions are two stepped surfaces l1 and i8. Substantially the upper half of the mandrel section 16 is smooth and the lower half is provided with acme or square threads l9, the pitch of which will be greater than the pitch of the usual joint V-type threads, but have the same direction which will be that permitting screwing up of the threads when the drill pipe is rotated in the drilling direction. The lower end of the section l6 has a short smooth section 20 and a second short smooth end section 2| of slightly reduced diameter.

Adapted to surround the section l6 of the mandrel is a barrel B, to the upper end of which is connected by a joint 22, employing V-threads, a sub 23 and to the lower end of which is connected by a joint 24, employing V-threads, a sub 25. The external diameters of the barrel and subs are the same as the drill pipe. The inner diameter of the barrel is somewhat larger in diameter than the section I6 of the mandrel which it is adapted to surround. The upper end of sub 23 has its inner diameter stepped in a manner to receive the stepped surfaces l1 and I8. Its outer end edge 26 is adapted to be engageable with an annular shoulder 21 on the inner end of the upper end l3 or the mandrel. O-ring seals 28 and 29 are carried in rooves in the surfaces I! and I8 has internal threads 33 of square cross section into which can be screwed the lower end. of the 7 section I of the mandrel. The lower end of sub 25 has male V-threads 34 to connect with usual female V-threads on the lowerdrill pipe portion l to provide a connectionwith-:said-pipe or direct to the drill collars as the case maybe.

When it is desired to use the unit as a bumper sub as, for example, when the drill collars and drill bit becomes stuck or for other reasons, the drilling string will be given a rotation in reverse to that of the drilling direction. This will cause the threads of the portion N5 of the mandrel to be unscrewed from the lower sub without unloosening anyjoints between any sections of drill pipe'jforming the string?" This'results from the fact that'square threads of different pitch are employed between the mandrel and the lower sub 25' rather than the regular V-threads at the other The sub 25 has a hardened upper end to provide a second anvil for a bumper or jarring function of the unit.

In surrounding relation to the mandrel .por.-.

tion l6 and arranged to be surrounded by'the.

grooves 31 and 38. These grooves are arranged With; this spline and groove arrangement between the to receive, respectively, splines 39. and ML nut and the barrel, the nut will be incapable of rotating relatively to'the barrel, but will be-Ir'ee to have longitudinal movement whenever this. movement is given to it by the mandrel upon. It willbe. noted that the which it is screwed. nut has a length considerably less than the distance between the two. anvil ends of the subs 23..

and 25, thus the nut is free to have longitudinal; movement so it can strike a hammer-like .blow.

against the anvils, depending upon which .direction the mandrel is moved. The ends of the nut.

will be hardened so. there. will be a hard surface.

by which to strike the hammer-like blows.

The mandrel on the portion I 6 thereofat a: point just above the upper ends of the threads;

I9 carries two O-rings 4| and 42 which will func-. tion as sealing means under certain conditions.

when the unit is conditioned tovperform bumper, or jarring functions, these conditions being pres-. ent when the tool is in the condition shown in Figures 3 and 4.

When my improved combination bumper sub j and safety joint unit is placed in a drilling string.- in the condition shown in Figures. 1 and 2, it will.

provide a rigid connection between drill pipe DOT? tions or a drill pipe portionand drill collars.

Under such conditionsitwill be noted that the mandrel portion [6 will be screwed into the lower' sub 25 to such an extent that the shoulder 2'1. on.

the upper end portion l3- of the mandrel will be in tight abutting engagement with .the end 2:6.-

of upper sub 23. All the O-rings, except 4] and 42 will be performing sealing actions. ,Thus, there will be no possibility of leakage of-fluid at, the unit as fluid is circulated under-pressure,

through the drill pipe and the bores in, the man-v drel and sub 25. Under the rigid connecting conditions the nut N will be at is lower position adjacent the lower sub 25. All the threads will have proper direction so they will be tightened by;

the direction of rotation of the drilling string .7

during drilling.

jointsin thedrillstring. As the mandrel is unscrewed from sub 25 the threads of portion I6 of v the mandrel will also be screwed through the nut since-the nut is held from rotation by its spline connection with the-barrel B. Upon the mandrel being unscrewed to a limited extent from sub 25, all as shown in Figures 3 and 4, the mandrel is then free to have limited free longitudinal movement with respect to the barrel, the extent ofrnoyement-being determined by the distance between the inner ends of the two subs 23 and 25, since the nut will be movable with the mandrel due to the screw connection therebetween which is still present, even though the mandrel has been disconnected from sub 25.

With the unit now in bumper condition, a jarring action can be given to that portion of the drilling string below the unit byproper longi-,

tudinal movement of the stringv above the unit. If; it;is desired to jar upwardly, then the upper, part of the string is lowered so the nut-is at its lower end ot relative movement and against sub :By nowgiving the. string a rapid upward pull; ,the mandrel and nut will move relatively tor the barrel B until the nut strikes the lower end. of ;upper---sub--; 23, this giving it a hammer-like blow and; jarring upwardly on all the string below the. unit. since such is rigidly connected to the barrel B. Successive blows can be given by movingthe mandrel downwardly and then again giving it a rapid upward movement.

,-I f; it is{des ire d to jar the string below the unit downwardly, then the. mandrel will be given a quick downward movement from a position where thenut N-is spaced upwardly from the lower sub; 25. It isof course obvious that alternate up and down jars can be-produced by reciprocating the mandrel with rapid movements in each direction; a

I When the unit ,is in bumping condition, as. shown in Figures 3 and 4 with the nut N in its, lowerpgsition, it will be notedthat the (Zr-rings. 4|. and 42-,a-re cooperating with the smoothbore 'of upper sub 23, thus sealing the mandrel with thebarrel Under such conditionsfiuid can still' be circulatedwithoutleakage.

If jarring should not-be effective. to loosen the. stuck; part; of the drill stringand it is desired-to disconnect the upper part of the string therefrom, or iffor any other reason disconnection is desired, such can be easily accomplished by the unit. Allthat needs to be done is give the man drel additional reverse rotation and the threaded. portion lfi willbe unscrewed from nut N sincethis nut-isbeing held from-rotation with the mandrel by its spline connection with the barrel. With the mandrel free, of the nut. all of the drill-.

,ing'string above the unit can be removed from the hole and a fishing operation undertaken. The .mandrel can be reconnected to the nut or to the sub 25- at any time byplacing the string with: the mandrelconnected to .its lower end the bore and rotating it in drilling direction Thus, bumping function can be commenced again or a rigid connection obtained. 1

It is to be noted that my improved combination bumper sub and safety joint is simple in construction and easily manufactured. 'Bumping or jarring in an up or down direction, or both, can be accomplished by its use. reverse rotations condition the unit for either bumping operations or complete disconnection of the drilling string. A sealed condition is present for circulation when the unit is manipulated to provide for either a rigid connection or bumping. Servicing the unit is simple. If the anvils or abutments receiving the hammer-like blows become badly deformed, all that needs to'be replaced to recondition the unit are the two subs 23 and 25 and the nut, all of which can be done in an easy manner.

Being aware of the possibility of modification in the structure disclosed as embodying my invention and all without departing from the fundamental principles thereof, I desire it to be understood that the invention is not to be limited in scope except in accordance with the appended claims.

What is claimed is:

l. A combination bumper and safety joint unit for inserting between portions of a drilling string, said unit comprising a mandrel connectable with one portion of the string and being provided with threads over a considerable length thereof, a barrel for surrounding the mandrel in radial spaced relation, a sub at each end of the barrel having an anvil portion positioned inwardly of the inside wall of the barrel, one of said subs being arranged for connection with the other portion of the string and having a threaded bore into which the mandrel can be screwed in the direction of drilling rotation of the string to thereby rigidly connect the unit in the string, a nut threaded on the mandrel and positioned within the barrel between the anvil portions of the subs, and means for mounting the nut for sliding movement with respect to the barrel but not relative rotation with respect thereto, said nut being of a length considerably less than the distance between the anvil portions.

2. A combination bumper and safety joint unit for inserting between portions of a drilling string, said unit comprising a mandrel connectable with one portion of the string and being provided with threads over a considerable length thereof, a barrel for surrounding the mandrel in radial spaced relation, a sub at each end of the barrel having an anvil portion positioned inwardly of the inside wall of the barrel, one of said subs being provided with connecting structure for connection with the other portion of the string and having a threaded bore into which the mandrel can be screwed in the direction of drilling rotation of the string to thereby rigidly connect the unit in the string, a nut threaded on the mandrel and positioned within the barrel between the subs, and spline means for non-rotatably connecting the nut with the barrel, said nut being of considerably less length than the distance between the anvil portions of the subs so that when the mandrel is unscrewed the barrel can have limited sliding movement with respect to the nut.

3. A combination bumper and safety joint unit for inserting between portions of a drilling string, said unit comprising a hollow mandrel connectable with one portion of the string and being provided with threads over a considerable length Simple thereof, a barrel for surrounding the mandrel in radial spaced relation, a hollow sub at each end of the barrel having an anvil portion positioned inwardly of the inside wall of the barrel, one of said subs being provided with connecting structure for connection with the other portion of the string and having a threaded bore into which the mandrel can be screwed in the direction of drilling rotation of the string to thereby rigidly connect the unit in the string, and a nut threaded on the mandrel and positioned within the-barrel between the subs, said nut being of a less length than the distance between the anvil portions of the subs and capable of being engaged by either anvil portion when the mandrel is unscrewed from the sub to thereby permit the accomplishing of either upward or downward jarring, and means providing a seal between the mandrel and barrel when the mandrel rigidly connects the unit in the string.

4. A structure for positioning as a unit between portions of a well drilling string comprising a mandrel for connection with one portion of the string, means including a member and cooperating threads on the member and mandrel for rigidly connecting the mandrel to the other portion of the string without any relative longitudinal movement, means operable upon a disconnection of the rigid connection of the mandrel and the other portion of string for so connecting the mandrel with said other portion of the string that the mandrel can have limited relative longitudinal movement with respect thereto, said last named means comprising a member connected to the said other portion of the string, a nut threaded on the mandrel, spaced abutments carried by the said member and positioned on opposite sides of the nut and capable of being given either upward or downward hammer-like blows by the nut upon a relative longitudinal movement of the mandrel, and means for holding the nut so that the mandrel can be unscrewed from the nut by a rotation of the said other portion of the drilling string in a direction opposite to the drilling rotation and thereby completely disconnect the two portions of the drilling string.

5. A structure for positioning as a unit between portions of a well drilling string comprising a mandrel for connection with one portion of the string, a barrel surrounding the mandrel, means for connecting the barrel with another portion of the string, means for rigidly connecting the mandrel and the barrel together, a nut interposed between barrel and mandrel and being threaded on the mandrel, means for connecting the nut to the inner part of the barrel so as to be slidable therein but rotatable therewith, means establishing an abutment on the barrel so positioned that the nut is free to have longitudinal movement so as to engage the abutment with a hammer-like blow, said mandrel and nut being so threaded together that the mandrel can be disconnected from the barrel by a rotation of the mandrel but the mandrel will remain connected with the nut so that upon longitudinal movement of the mandrel and nut as a unit a jarring action can be given to the barrel and the portion of the string to which it is connected.

6. A structure for positioning as a unit between portions of a well drilling string comprising a mandrel for connection with one portion of the string, a barrel surrounding the mandrel, means for connecting the barrel with another portion of the string, means comprising threads for rigidly connecting the mandrel and the barrel together, a nut interposed between barrel and mandrel and being threaded on the mandrel, means for slidably but non-rotatably connecting the nut to the inner part of the barrel, and spaced abutment means carried by the barrel and so positioned in spaced relation on opposite sides of the nut that the nut is free to have longitudinal movement therebetween before engagement with either abutment, said mandrel and nut being so threaded together that the mandrel can be disconnected from the barrel by the threaded connection but remain connected with the nut so that upon longitudinal movement of the mandrel and nut as a unit a jarring action in either direction can be given to the barrel and the portion of the string to which it is connected by a selective engagement with the abutments.

7. A structure for positioning as a unit intermediate portions of a well drilling string comprising a mandrel for connection with one portion of the string, a barrel surrounding the mandrel, means for connecting the barrel with another portion of the string, means comprising threads for rigidly connecting the mandrel and the barrel together, a nut interposed between barrel and mandrel and being threaded on the mandrel, means for slidably but non-rotatably therebetween but still remain connected with the nut so that upon longitudinal movement of the mandrel and nut as a unit relative to the barrel a jarring action can be given to the barrel and the portion of the string to which it is connected. said mandrel also being capable of becoming completely disconnected from the nut and also the barrel by an unscrewing action in addition to that necessary to disconnect the rigid connection.

KENDALL R. STOHN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,621,583 Creighton Mar. 22, 192'? 1,775,673 Fields Sept. 16, 1930 2,499,695 Storm Mar. 7, 1950 

